Though we have no evidence of what to find in the wastes of Fallout 4, I put 2 and 2 together to come up with some theories on what we can expect. So Here we go...
Because it is confirmed that there is a modified Gamebryo engine that will most likely be used in Fallout 4, we can expect:
Dual-Wielding One handed weapons
Dynamic Melee Combat
Smoother Graphics, and more environmental movement
A sprint button, much like Skyrim.
These are just theories though, so don't flame me. Also, we may find Radiant AI returns from Skyrim, but its just a possibility.